Pin for artificial teeth and method of producing same



Dec. 3, 1935. J. o. WHITELEY PIN FOR ARTIFICIAL TEETH AND METHOD OF PRODUCING SAME Filed May 15, 1934 i NVENTOR. Jose h 0. Whiieley. y

- oi'ney-.

Patented Dec. 3, 1935 PATENT OFFICE PIN FOR. ARTIFICIAL TEETH METHOD OF "PRODUCING SAME Joseph-0. Whiteley, York, Pa, assignorto .The

Dentists Supply Company of New York, a'corporation of New York Application May 15, 1934,-Serial:No.725,690

"3 Claims.

The object of my invention is to provide an anchoring pin, for artificial "teeth, which will be strong and durable in constructionand include protection against deleterious effects due "to oxidation and presence of acids in the oral fluids, andwhichalso has capacity to prevent injury :to the pin during various-heat changesrequired in the manufacturing processes.

:In' carrying'out the invention it is my primary purpose 'to construct a composite wire having a 3C0IeIOfkStl0Ilg' base metal and provided'with one :or'more covering layers of precious metals or alloys thereof, the same being 'mechanically or physicallyapplied to thecore toiorma close and dense structure which will be impervious to gases, acids and otherdestructive solutions, and adapted to being hammered. swaged, rolled or "drawn "into a fine-wire, which 'isthereafter-cut and .shaped to form individual pins for artificial'teeth;

for their properties which are chemically inert to the base metal core and #capable of withstanding frequent annealings during the *wire producing process.

the-"saidcovering layer or layersbeing selected Still :further, it is my intention to apply a precious :metal covering "layer to the pins'after having been cut and formed from the drawn wire, which outer covering layerfis electrolytically *applied'soas to fully 'cover'both'the head and tshank'portions of the pin, giving toit-not only an ornamental finish which is'self-retaining but :also affording additional protection against "in- 'jury'tothe pin when in use'in adenture.

Accordingto theinvention,the'dentalfipin comprises'a'base'metal core with a jacketwofdensiifled' precious metal chemically inert to "the core *coveringallbutthe head,crwn and'foot of said pin,-and*a uniform outer covering of homogeneous preciousmetal completely encasingthe pin. The

pin is'm'ade'by first mechanically applying a covering o'f 'preciousmetal to a base metal corejthen compressing same into a fine wire, then cutting and shaping the 'densified 'wire into tooth pin forms, andfinally'coveringthe entireipin with an :outer layer of'precious metal.

low' cylindrical covering of precious metal;

Fig. -3 is-a longitudinal sectional view illustrat- -ing a ;pin structure whose shank has been stretched-or-elongated and whose head has been 'upset;swaged and compressed, the same having a :baseemetal core and a covering layer of precious metal;

" Fig. 4 is asimilar view to that shown in Fig. 3, butwith an i'ad'ditionalrcovering layer of non-corrodible-precious metal which entirely covers the outer surface "of the pin;

Fig. 5 is "a cross-section of the pin taken on: line 4-1 of Fig.4 and Fig. fiis 'an enlarged sectional View of the'head ofthe pin,'to'more clearly illustrate these coveringstructures.

Broadly considered, my improved pinembodies a-structure comprising a'base metal core 2, one or more mechanicallyimpose'd covering layers 3 of precious metal or a suitable alloy thereof, and which, after being properly shaped, is finally coated by 'an electrolytically deposited covering .20

4 of precious metal, preferably gold, which is especially resistant vto oxidation and acids in the -toral fiuids.

-In the production of'my improved pin structure, I'employ a strong base metal core 2, either .25 of nickeL'ta'ntalum; tungsten and the like, which, while "being relatively inexpensive and durable, "are reslstantto high temperatures. These metals have, however, a'relatively low resistance or defensetagztinst oxidation and acids of the mouth, -and' hence must be protected'by one or more-covering layers'of precious metals which'will be resistantto such deleterious effects. Such covering layer maybe of silver, gold, any metal of the "platinumgroup, or a'suitable alloy of the pre- *cio'usmetals, such as'would be included in an alloy of palla'dium and silver, and by my present *mthodQis mechanically or physically applied to the basemetal core.

The advantage of amechanically or physically 40 "appliedoovering layer to the basemetal core is that, due to "being hammered, rolled, drawn, swaged or-the like, the covering will have a dense 'close'grain structure which is impervious to acid solutions and gases and provides the base metal core 'with aprotecting covering, whereasa covering'applied by electro-deposition Would, through "the crystallinecharacter of the layer, be more or' less porous'and hence, if'used alone, would fail as a'protecting layer or covering for the base metal. For this reason, the use lot a' dense buffer layer association with an electrolytically depositedxlayer will insure the physical protection of the pin, and the outer electrolytically deposited ilayer lpreferably gold) will further assure the permanency of the desired external color and beauty of surface. Furthermore, the mechanically or physically imposed covering layer may be fairly thin, if so desired, thus reducing the cost and quantity of precious metals used in covering the base metal core, since the structure, according to my invention, is to be further protected by an electrolytically deposited covering of precious metals.

After the base metal core structure 2a has been mechanically or physically covered with one or more layers 3a of precious metals, it is then reduced by means of rolling, swaging anddrawing, with frequent annealings, into a fine wire suitable for cutting and shaping 'into tooth pin forms for use with artificial teeth. Where mechanically applied layers only are used, the necessity of frequent annealings in reducing thethick wire to a fine wire has a tendency to causethe underlying base metal core to penetrate the precious metal covering and cause it to oxidize and discolor,'and for this reason a fairly heavy covering of precious metal is necessary to resist the infiltration tendency of the metal of the underlying core where such mechanically applied layers onlyare used. Furthermore, in the cutting and shaping of the tooth pin forms from the fine wire, the covering layer 3 immediately outside of the base metal 2 is crowded inward in the upset portion to impart, to a more or less degree, a closure at both ends of the pin. This closure, however, while covering a. part of the head and shank ends of the pin, leaves a portion of the base metal core 2 exposed in said parts,

'as indicated at 5 and 6, thus permitting injury to the pin when subjecting-the same (while atuse in a denture.

To overcome these defects, I combine, with the mechanically applied layer, an electrolytically deposited or applied outer layer 4 of precious metals, such as silver, gold, any of the platinum group metals, or suitable alloys of these metals, to the pin structure. By combining a mechanical and an electrolytically applied covering to the base metal core, the mechanical covering may be selected, because of its properties, to act as a chemical buffer between the core and the electrolytically applied covering, and by reason of which will prevent the formation of a gold-nickel eutectic. For example, in the case of a tooth pin with a nickel core and a pure gold covering, I find that under heat the nickel and gold have an afiinity for each other, such thatthe nickel will alloy with and discolor the gold at a temperature lower than the melting point of either metal. Gold and nickel form a eutectic or melting point around 1700" to 1800 F. Therefore, in the case of a nickel pin with a single a mechanically applied gold covering, the gold covering must be relatively thick, which is expensive. In my present method, I employ inner and outer coveringsor layers of precious metals, both of which may be relatively thin, thus considerably reducing the cost and quantity of precious metals necessary to form such coverings or layers. Furthermore, because of 'the combination mechanically applied inner layer and electrolytically deposited outer layer, certain advantages are obtained; for example, the outer layer need not be subjected to the frequent annealing temperatures necessary when applying the mechaniof desirable color.

cal layer of precious metal to the core, or when working down the bar or structure as in the manufacture of wire, because such repeated annealing heats would require the coverings to be fairly heavy in order to avoid the tendency of the 5 gives to the pin an ornamental covering of de- 15' sirable color and surface beauty.

Heretofore, in the method of making mechanically plated articles, such as tooth pins, the method was as follows: A nickel bar is covered mechanically with a layer of silver and then 20 -mechanically again covered with an outer layer of gold. The gold in such a case was 'quite thick in order to resist the tendency of the silver layer to penetrate and blanch its color when heated. When a wire so constructed was're- 25 duced and tooth pins out therefrom, a spot of nickel was exposed on the head and shank ends of the pin. In my improved method, these objections are entirely overcome and a tooth pin is produced which will withstand not only dele- 0 terious effects due to oxidation and acids in the oral fluids, but is, completelycovered from head to shank end with a covering of precious metal According to my improv d method, I first cover the base metal bar with a 35 mechanically applied layer orlayers of precious metal or a suitable alloy thereof, selecting a metal which'will be chemically inert to the core metal and which has the properties desired for the particular application and use to which'the 40 bar is subjected; I then work the bar into a fine wire by rolling or drawingyand thereafter cut and form the wire into tooth pins. The formed pins are then electro-plated or gilded with a precious metal of desirable color and chemical 5 properties to thoroughly protect the pins against gases and oral fiuids. The pin thus made is therefore provided with a uniform outer covering of homogeneous precious metal completely encasing the pin. A tooth pin so constructed 50 has every desirable advantage over pins constructed under the old method; and in addition is relatively inexpensive, as both the inner and outer coveringsmay be thin; repeated applications of heat necessary to work 'down the bar 55 into a fine Wire structure are avoided;' the entire pin from head to shank ends is completely covered witha protective layer of precious metal; and the completed pin presents an ornamental finish of desirable color and surface beauty fully 60 protected against deleterious efiects and insolubility in oral solutions.

Of course the tooth pins shown and described herein may be modified in various ways without departing from the invention herein set forth and hereafter claimed.

I claim: f

1. A pin for artificial teeth, comprising a base metal core, a jacket of densified precious metal chemically inert to the core and covering all but 70 the head crown and foot of said pin, and a uniform outer covering of homogeneous precious metal completely encasing the pin.

2. The herein described method of making a pin for artificial teeth, comprising thesteps of II first mechanically applying a covering of precious metal to a base metal core, then compressing same into a fine wire, then cutting and shaping the densified wire into tooth pin forms, and 5 finally covering the entire pin with an outer layer of precious metal.

3. The herein described method of making a pin for artificial teeth, which consists in mechanically applying a covering of precious metal to a base metal core and. compressing the same into a fine wire, thereafter cutting and shaping the densified wire into tooth pin forms, and finally electrolytically depositing upon the entire surface of the tooth pin forms an outer covering or layer of precious metal.

JOSEPH O. WHITELEY. 

